#define echoPin 7 // Echo Pin
#define trigPin 8 // Trigger Pin
#define LEDPin 13 // Onboard LED
int maximumRange = 200; // Maximum range needed
int minimumRange = 0; // Minimum range needed
long duration, distance; // Duration used to calculate distance

void setup() {
  Serial.begin (9600);
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  pinMode(LEDPin, OUTPUT); // Use LED indicator (if required)
} 

void loop() {
  /* The following trigPin/echoPin cycle is used to determine the
  distance of the nearest object by bouncing soundwaves off of it. */
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  duration = pulseIn(echoPin, HIGH);
  //Calculate the distance (in cm) based on the speed of sound.
  distance = duration/58.2;
  if (distance >= maximumRange || distance <= minimumRange){
    /* Send a negative number to computer and Turn LED ON
    to indicate "out of range" */
    Serial.println("out of range");
    digitalWrite(LEDPin, HIGH);
  } else {
    /* Send the distance to the computer using Serial protocol, and
    turn LED OFF to indicate successful reading. */
    Serial.print("Objeto a: ");
    Serial.print(distance);
    Serial.println(" cm.");
    digitalWrite(LEDPin, LOW);
  } //Delay 50ms before next reading.
  delay(50);
}